1. Field
An embodiment of the inventive concepts described herein relates to a method of forming external terminals of a package and an apparatus configured to perform the same. More particularly, an example embodiment relates to a method of forming solder balls on a package substrate of a semiconductor package, and an apparatus configured to perform the method.
2. Description of the Related Art
Generally, various semiconductor fabrication processes may be formed on a wafer for a plurality of semiconductor chips. In order to mount the semiconductor chips on a printed circuit board (PCB), a packaging process may be performed on a semiconductor chip to form a semiconductor package.
The semiconductor package may include a package substrate, a semiconductor chip, conductive connecting members, a molding member and external terminals. The semiconductor chip may be arranged on an upper surface of the package substrate. The conductive connecting members may electrically connect the semiconductor chip with the package substrate. The molding member may be formed on the upper surface of the package substrate to cover the semiconductor chip. The external terminals may be mounted on a lower surface of the package substrate.
According to related arts for forming the external terminals, the package substrate may be adhered to a jig using a vacuum. A mask having a plurality of openings may be arranged on the package substrate. The external terminals, such as solder balls, may be supplied to the package substrate through the plurality of openings of the mask.
The jig may be configured to fix only a central portion of the package substrate using the vacuum. Thus, an edge portion of the package substrate may not be firmly secured. This may result in upwardly protruding edge portion of the package substrate. Therefore, a portion of the mask that makes contact with the upwardly bent edge portion of the package substrate may also be upwardly bent. A solder ball passing through an opening of the upwardly bent portion of the mask may have a thickness greater than that of a solder ball passing through an opening of other portions of the mask. As a result, the solder balls on the package substrate may not have uniform thickness.